Several poor prognostic factors are known to be related to MDA5-DM, including the presence of ILDs (13), an anti-MDA5 antibody titer ≥500 U/L (14), ferritin ≥636 ng/mL, LDH ≥355 U/L, CRP ≥0.8 mg/dL, KL-6 ≥1000 IU/mL (15), age>50 (16) and anti-SSA/Ro52 antibody positivity (17, 18). Here, TRIM21 is linked to dermatomyositis.